Computer systems typically include components that generate/dissipate considerable amounts of heat. These components may include one or more processors (e.g., central processing units, multi-chip modules, etc.), system boards having printed circuit boards (PCBs) in general, memory, power supplies, and other circuits. In recent years, these components have become more dense and, hence, generate more heat during operation. Excessive heat tends to adversely affect the performance and operating lives of these components. Furthermore, when a plurality of computer systems are stored in the same location, as in a rack, there is an even greater potential for the adverse effects of overheating.
In order to substantially guarantee proper operation, and to extend the life of the computer systems, it is necessary to maintain the temperatures of the components within predetermined safe operating ranges. Operation at temperatures above maximum operating temperatures may result in irreversible damage to the components. In addition, it has been established that the reliabilities of components, such as semiconductor electronic devices, decrease with increasing temperature. Therefore, the heat dissipated by the components during operation should be removed at a rate that ensures that operational and reliability requirements are met.
Cooling systems are used to remove heat generated by components in computer systems. Cooling systems may include fans, air conditioning units, cooling liquid, etc., to facilitate heat dissipation. Racks housing multiple computer systems generally utilize a cooling system to cool the computer systems.
Typically, the distribution of work among the computer systems in the rack is random and is not controlled. Because of work distribution, some components of the computer systems may be operating at a maximum capacity, while at the same time, other components may be operating at various power levels below a maximum capacity.
Regardless of the power level and heat dissipation of components at varying power levels, cooling systems are typically designed to uniformly cool components based on a maximum heat dissipation of the components. That is cooling systems are designed to remove heat from components as if the components are continually operating at maximum capacity or power levels (i.e., in an operating state where the components are dissipating the maximum amount of heat). Furthermore, cooling systems are typically designed to cool computer systems that are fully provisioned (i.e., fully upgraded). For example, a computer system may be upgraded (or provisioned) by adding or replacing components (e.g., faster processors, more memory, etc.) that dissipate more heat. Typically, a cooling system is used that is capable of sufficiently cooling a fully provisioned computer system, regardless of whether the computer system has been fully provisioned.
Generally, components of computer systems do not continually operate at maximum capacity and computer systems may operate at varying power levels over time. For example, one server may have a heavier workload than another server at any given time. Consequently, conventional cooling systems, which are designed to cool computer systems continually operating at maximum capacity, may be energy inefficient, more expensive and more complex than necessary for adequately cooling heat generating components of one or more computer systems.